Film development spool



March 29, 1938. E. PLESS 1 ,60

FILM DEVELOPMENT SPOOL Filed June 13, 1956 lll INVENTOR.

- ATTORNEY.

artist APLeas' Patented Mar. 29, 1938 FILM DEVELOPMENT SPOOL Ernst Pleas, Mauer, near Vienna, Austria, as-

signor of one-half to Hermann Dannowski,

Jackson Heights, N. Y.

- Application June 13, 1936, Serial No. 85,010

In Austria June 13, 1935 .2 Claims. icl. 242-104) This invention relates to devices for developing photographic films commonly known as developing tanks. In the use of such devices, the film afterexposure in a camera is spirally wound upon a support such as a spool with the-adjacent spiral windings properly spaced from each other. The spool is then placed in a receptacle or tank and the developing solution poured into the tank. The developing process may be carried out in a '10 dark room or daylight. In the latter case, the

tank is closed by a light tight cover.

After a specified developing time dependent on the developer used, the temperature, etc., the solution is poured out and the film fixed and rinsed in the commonly known manner.

The present invention is specifically concerned with a spool for holding the film to be developed and has for one of its objects to provide-a developing spool adapted to accommodate different sizes of films available on the market to avoidthe necessity of using a different developing device for each particular film sire. Another; object is to facilitate the insertion and winding of the film} into a developing spool and to prevent jamming and other drawbacks experienced with similar devices known in the art. Another object is to provide a means to insure free access of the developer to all portions of the sensitive surface especially to.the' edges of the film to secure uni- 30 formly developed negative.

With the ab0ve objects in view, the film holding device or developing spool described by this invention comprises substantially two disc shaped parts or flanges mounted upon and spaced by a central member. The discs are formed with spiral guides parallel to'each-other for guiding the film during the winding operation and maintaining adjacent windings properly spaced during thedeveloping process. In order to accommodate different film sizes, the distance -between the discs is made adjustable to conform to the standard widths of film available on the market. Another feature consists in the construction of the ingress openingfrom the periphery of the r discs to the spiral guide to enable an easy insertion and winding of the film even in full darknesswithout clogging or jamming.

These and further objects of the invention will become more apparent by the followingdetailed description taken with reference to the accompanying drawing in which 7 Figures 1 and 3 are a top and side view, respectively, of one part of the developing spool.

Figures 2 and 4 are a top and side view, respectively, of the other of the developingspool.

Figure 5 shows the two parts mounted ready for insertion and winding of the film.

Figure 6 illustrates a modification of a spool according to the invention.

Similar reference numerals identify similar 5 elements in the dilferent views of the drawing.

Referring to Figures 1 and 3, these illustrate the lower part A of the spool comprising a disc or flange I having a spiral guide 9 preferably formed integral therewith by a thin spiral shaped 10 wall at right angles to the disc surface for'insertion and guiding of the film through the ingress opening 2. The disc I has a central tubular extension 3 provided with a longitudinal guide groove I, the purpose of which will be described later. The tube 3 is provided with a plurality of circular grooves 5 suitably spaced from each other conforming to different widths of standard film sizes. v

The upper part B of the spool as shown in Fig-' pres 2 and 4 comprises a disc I1 I provided with a spiral guide 9' and an ingress opening 2' substantially similar'as in the case of part A. The

disc I has a central extension or sleeve I having an inner diameter adapted to fit snugly over the central tube 3 of part A as shown in Figure 5. The sleeve 1 is provided with a plurality of longitudinal slots 6 to secure a certain degree of resiliency and ensure frictional engagement with the tube 3 of part A. In order to secure the prop- '10 er alignment of the spiral guides 9 and 9' of parts A and B and prevent relative rotation thereof, the sleeve 1 is further provided with a longitudinal guide I projecting from its inner surface and adapted to engage the groove 0 of the center tube 3 of part A.

In order to facilitate the insertion of the edge of the film into the spiral guide, the ingress openings 2 and 2' to the film guides are formed with edges tapering gradually from the outer surface 40 of the discs towards the inner surface thereof and terminating in the spiral guides as shown in the drawing. In this manner. the film may be inserted into the spiral guide even in complete darkness by merely pushing it into the openings 2 and 2' until it has been completely wound inside the spool.

In order to lock part B or upper disc in the different positions corresponding to the particular widths of film used, the,inner surface of sleeve 1 is furthermore formed with a circular projection or collar ll (see Figure 2) adapted to snap into and out of the grooves 5 of tube 3 when part B or lower disc is moved along the center tube 3 as shown in Figure 5.

Insome cases it beeniound mgeousiitheentireedgeoitheiilmisindirectconwith thewalls of thespiral Iilidfl land O tuberances ll projecting from the spiralguideslor l'servingtokeeptheedge the dim spaced from the guide free access oi the developer. In the developing solution to pass space between the spiral windings oi the thediscsland l'aresuitablyprovided openings or slots in a manner well known.

for illustration, and that variations and modifications thereof are possible coming within the broader scope and spirit of the invention as delined in the appended claims.

Having thus described my invention what I claim as newand desire to secureby Letters Patent is:

1. A developing spool comprising a pair of end membershavingspiral ,posite'andparaileltoeachotherandadaptedto' irictionally engage said iirst sleeve, whereby said sleeves form a hub for said spool, one of said sleeves bdng formed with a plurality oi circular grooves spaced 'apart by predetermined distances, ,and a collar on the e surface 0! the other sleeve being adapted to engage said grooves and lock said end members at predetermined axial distances, and a further longitudinal key and groove arrangement between said sleeves to prevent relative rotary movement thereof. 

